1. Field of the Invention
The present invention relates generally to light emitting diode (LED) lighting devices and more particularly to LED lighting modules having heat transfer properties that improve the efficiency and performance of LEDs.
2. Description of the Related Art
Most lighting applications utilize incandescent or gas-filled bulbs, particularly lighting applications that require more than a low level of illumination. Such bulbs typically do not have long operating lifetimes and thus require frequent replacement. Gas-filled tubes, such as fluorescent or neon tubes, may have longer lifetimes, but operate using dangerously high voltages and are relatively expensive. Further, both bulbs and gas-filled tubes consume substantial amounts of power.
In contrast, light emitting diodes (LEDs) are relatively inexpensive, operate at low voltage, and have long operating lifetimes. Additionally, LEDs consume relatively little power and are relatively compact. These attributes make LEDs particularly desirable and well suited for many applications. However, one limitation of LEDs is that they typically do not provide sufficient brightness for applications that need more than low level illumination.
Although it is known that the brightness of the light emitted by an LED can be increased by increasing the electrical current supplied to the LED, increased current also increases the junction temperature of the LED. Increased junction temperature may reduce the efficiency and the lifetime of the LED. For example, it has been noted that for every 10° C. increase in temperature above a specified temperature, the operating lifetime of silicone and gallium arsenide drops by a factor of 2.5–3. LEDs are often constructed of semiconductor materials that share many similar properties with silicone and gallium arsenide.
Another factor in the use of LEDs is that, in most systems, a series of LEDs must be connected together and mounted on a surface. Such connection and mounting is typically a time consuming, laborious process.
Accordingly, there is a need in the art for a convenient and efficient arrangement for mounting LEDs on a surface. There is also a need in the art for lighting systems utilizing LEDs that provide illumination at levels which are more comparable to those of incandescent bulbs and gas-filled tubes.